Many surgical procedures require the use of specialized tools to perform surgical tasks with a high degree of accuracy and precision. In some cases, such surgical procedures require precise positioning and/or placement of the tool at or near a particular point within a patient's anatomy. For example, many orthopedic procedures rely on the accurate placement of pins, screws, guide and/or post holes, or other elements in a precise position and orientation with respect to an anatomical feature of the patient. In order to ensure that these elements are properly positioned and oriented, great care is required on the part of the surgeon to ensure that the surgical tool(s) (e.g., drill, saw, reamer, etc.) used to position these elements is precisely and accurately aligned with the anatomy of the patient. However, this can be particularly challenging without the use of a guide and even more challenging in minimally-invasive procedures where visibility at the surgical site is limited or, in some cases, nonexistent.
Early solutions for enhancing the accuracy and precision of the alignment of tools in a surgical environment involved the use of mechanical guide elements, such as jigs. These mechanical guides were typically placed and/or mounted in close proximity to the anatomy of the patient and provided a physical guide that maintained a desired position and orientation of the tool during its operation.
For example, some prosthetic implants used in knee joint replacement surgeries comprise projections, keels, and/or other mechanical elements that are configured to fit within corresponding holes or voids created in the bone to secure the implant to the bone. In order to ensure the accurate placement of these voids, a jig was often used to mechanically align a drill in a desired position and orientation with respect to the bone of a patient. During operation of the drill, the jig would maintain the desired orientation while the surgeon advanced the drill into to the bone until the desired depth was reached.
Although these guide jigs enhanced the accuracy and precision of the placement of voids within the bone, they needed to be physically installed in proximity to the bone during the surgical procedure. The accurate alignment and placement of these guides can take a considerable amount of time, which could prolong the surgical procedure. Furthermore, mechanical jigs and cutting guides are typically too large to fit within the relatively small spaces allowed for minimally-invasive procedures.
With the advent of computer-assisted surgery (CAS) systems, surgeons were no longer required to rely on mechanical jigs for precision positioning of surgical instruments. Specifically, many CAS systems include surgical navigation and tracking software that displays a graphical representation of the surgical site. Using the navigation and tracking features of the CAS system, the surgeon can view the location of a surgical instrument relative to the patient's anatomy. Using the graphical interface as a guide, the surgeon can manually navigate the surgical tool to a desired position within the surgical site.
More sophisticated CAS systems are configured for interactive coupling with the surgical tools. These CAS systems may be equipped with force feedback controls that provide the surgeon with haptic feedback when, for example, the surgical tool interacts with certain pre-established virtual boundaries. Such virtual boundaries may be established to constrain the surgical instrument from undesired interactions with certain areas of the patient's anatomy. By strategically arranging the virtual boundaries for the force feedback controls, users can create “virtual” guides that define the areas in which the tool can operate, as well as areas that prohibit tool operation. If a surgical procedure requires the drilling of a post hole in a patient's bone, a virtual boundary may be established to define the desired position, orientation, and size of the hole. The virtual boundary may constrain a surgical tool from operating outside of the established boundary.
Although existing virtual guide methods provide a solution for defining the areas of allowed operation (and corresponding areas of constrained operation) of a surgical instrument, they may still be inefficient. For example, conventional virtual guide methods do include a solution for aligning a surgical tool in a proper orientation prior to engagement with the patient's anatomy. As a result, in surgical procedures that require precision cuts having specific orientations (such as the drilling of post or guide holes within bone), the surgeon may be required to manually “search” for the appropriate orientation by using the tip of the surgical tool as an exploring device to first locate the engagement point at the surface of the patient's bone. Once the engagement point has been located, the surgeon then manually pivots the surgical tool to locate the appropriate orientation for advancing the tool to the target point. Not only is such a manual process frustrating to the surgeon, it may unnecessarily prolong the surgery, which can increase costs.
The presently disclosed systems and methods for guiding a surgical instrument to a target orientation and/or position are directed to overcoming one or more of the problems set forth above and/or other problems in the art.